JP3786205B2 - Radar wave observation device - Google Patents

Description

ここで、ｆ（ｎ，ｍ）はレーダデータ、Ｆ（ｋ，ｌ）は空間スペクトルである。また、ｎ，ｍは座標値、ｋ，ｌは波数を表す。
【００３３】
次に、連続するスキャンのレーダデータに対する２次元ＦＦＴ値間のクロススペクトルＰ_Ｃ（ｋ，ｌ）を求める。
【００３４】
【式２】

【００３５】
次に、この２次元クロススペクトルＰ_Ｃ（ｋ，ｌ）の各ポイント毎の振幅スペクトルＳａ及び位相スペクトルＳφを算出する。各ポイントのクロススペクトルＰ_Ｃ（ｋ，ｌ）は、複素数で表現されるから、その実数部をＲｅ、虚数部をＩｍとすると、式（３）、式（４）で表される。
【００３６】
【式３】

【００３７】
【式４】

となる。なお、ａｔａｎは、アークタンジェントを表す。
【００３８】
このようにして、連続する２スキャンのレーダデータに対する２次元ＦＦＴ値間のクロススペクトルＰ_Ｃ（ｋ，ｌ）及びその振幅スペクトルＳａ及び位相スペクトルＳφを求める。
【００３９】
平均化手段２４では、２次元演算手段２３から供給される２次元クロススペクトルＰ_Ｃ（ｋ，ｌ）の各ポイント毎の振幅スペクトルＳａ及び位相スペクトルＳφを所定回数Ｎ（例えば３２回）だけ加算し除算して、振幅スペクトルＳａ及び位相スペクトルＳφの平均値を求める。この平均化の処理は、連続する２スキャンのデータを入力しながら処理が行われるので、電波干渉がない場合にはＮ＋１スキャンのデータを平均することになる。この平均化により、振幅スペクトルＳａ及び位相スペクトルＳφの２次元クロススペクトルＰ_Ｃ（ｋ，ｌ）毎の値のばらつきが吸収されるから、以後の演算・解析が安定して行われることになる。
【００４０】
波浪スペクトル推算手段２５では、まず、平均化された２次元クロススペクトルＰ_Ｃ（ｋ，ｌ）から振幅スペクトルＳａのピーク値を求める。このピーク点の位相スペクトルＳφに対応する位相をφとすると、計算波速Ｗｖｃは、式（５）により求められる。
【００４１】
【式５】

但し、Ｄは辺の長さ、ｋ、ｌは二次元クロススペクトル上の波数、Ｔはレーダのスキャン時間である。
【００４２】
一方、波の性質から、波の理論式である波速関係式により決定される理論波速Ｗｖｔ は、式（６）により、求められる。
【００４３】
【式６】

但し、Ｗｌは、波長である。
【００４４】
なお、この理論波速を決める波速関係式は、次のようにして求められる。一般に波の分散関係式は、式（７）で表される。
【００４５】
【式７】

ここで、ｄは水深、ｋ_ｖは波数ベクトル、Ｕは表面の流れである。水深が深くなるとｔａｎｈ（）の項はなくなり、Ｕ＝０の場合は、分散関係式は、式（８）になる。
【００４６】
【式８】

この分散関係式ωに、波速の一般式Ｗｖｔ ＝ω／ｋ_ｖを適用し、ωを消去すると、ｋ_ｖ＝２π／Ｗｌ だから、式（６）が求められる。
【００４７】
このように、一方では、計算波速Ｗｖｃが、ピーク点の振幅スペクトルに対応する位相スペクトルＳφ、その二次元クロススペクトル上の波数により計算され、他方では、理論波速Ｗｖｔ が波長、言い換えれば二次元クロススペクトル上の波数により計算される。
【００４８】
したがって、ピーク点の振幅スペクトル及びそれに対応する位相スペクトルＳφが本来の波によるものであるか、或いは雑音によるものであるかは、計算波速Ｗｖｃが理論波速Ｗｖｔ に整合するか否かによって、決定することができる。この整合の程度は、計算波速Ｗｖｃが理論波速Ｗｖｔ に対して例えば±１０％以内の差であれば、整合していると判定する。このときの計算波速Ｗｖｃが、求める波速となる。なお、フィルタリングの結果、計算波速Ｗｖｃが理論波速Ｗｖｔ に整合しなかった場合には、そのときの振幅スペクトル及び位相スペクトルは、本来の波のものではないので利用されない。
【００４９】
この結果、計算により求められた２次元クロススペクトルの振幅スペクトルＰ_Ｃ（ｋ，ｌ）の振幅スペクトルＳａ及び位相スペクトルＳφは、波浪スペクトル推算手段２５でフィルタリングされ、本来の波の振幅スペクトルＳａ及び位相スペクトルＳφが出力され、シーステート解析手段２６に供給される。
【００５０】
シーステート解析手段２６では、波浪スペクトル推算手段２５でフィルタリングされた本来の波の位相スペクトルＳφについて、そのピーク値周辺±Ｌの座標内で重心を求め、その位相スペクトルの重心から、波長Ｗｌ及び波向Ｗｄをそれぞれ、式（９）、式（１０）により求める。
【００５１】
【式９】

【００５２】
【式１０】

【００５３】
さらに対応する位相スペクトルＳφに基づいて波速Ｗｖｃを波毎に、例えば振幅スペクトルＳａの大きい波について算出する。
【００５４】
また、波浪スペクトル推算手段２５でフィルタリングされる前の振幅スペクトルＳａの総和Ｗを算出し、シーステート解析手段２６で２次元クロススペクトルの振幅スペクトルＳａのピーク点及びその周囲所定範囲の振幅スペクトルの和Ｓを算出し、予め求めておいた回帰係数Ａ，Ｂに基づく回帰式により、波高値Ｗｈを、Ｗｈ＝Ａ＋Ｂ×｛Ｓ／（Ｗ−Ｓ）｝により求める。波が複数である場合には、それぞれ各ピーク点のポイント及びその周囲所定範囲の振幅スペクトルの和Ｓ１，Ｓ２・・・を算出し、各波高値を、計算式Ｗｈ１＝Ａ＋Ｂ×｛Ｓ１／（Ｗ−Ｓ１ーＳ２・・・）｝、計算式Ｗｈ２＝Ａ＋Ｂ×｛Ｓ２／（Ｗ−Ｓ１ーＳ２・・・）｝・・・、により求める。この波浪演算処理器２０として、特許文献１に開示されたレーダ波浪測定装置を用いることができる。
【００５５】
次に、図１の波高補正処理器３０において、波浪演算処理器２０で求められた波向情報Ｗｄ、波高情報Ｗｈ（以後、演算波高情報Ｗｈ）、波長情報Ｗｌ、波速情報Ｗｖｃが入力され、演算波高情報Ｗｈの補正処理を行って、補正された波高Ｗｈｃ（以後、補正波高Ｗｈｃ）を出力する。
【００５６】
この図１の波高補正処理器３０における、演算波高情報Ｗｈの補正処理は、超音波波高計等による参照波高と演算波高情報Ｗｈとの差が大きくなる現象と、その他の波浪情報（波向情報Ｗｄ、波長情報Ｗｌ、波速情報Ｗｖｃ）との関連を発見したことに基づいて行われている。
【００５７】
超音波波高計は、海底から海面に向かって超音波パルスを発信し、パルスが海面で反射して戻ってくるまでの経過時間を距離に換算して、海面の高さを測定して、参照波高を得る。参照波高を得るための波高計としては、超音波波高計に限らず、他の波高計、例えば、容量式／抵抗式波高計、レーザ式／電波式波高計等、を用いることができる。
【００５８】
演算波高情報Ｗｈの補正処理は、具体的には、波浪情報（波向情報Ｗｄ、演算波高情報Ｗｈ、波長情報Ｗｌ、波速情報Ｗｖｃ）の取得と並行して、参照波高の測定を長期間にわたって行い、参照波高と演算波高Ｗｈ等とを比較した。その比較によれば、参照波高と演算波高Ｗｈとがほぼ一致する場合もあるが、全体としてみれば参照波高が高いときに演算波高Ｗｈが参照波高に相応して高くならず、参照波高が低いときに演算波高Ｗｈが参照波高に相応して低くならない傾向があることや、波向情報Ｗｄの変化が参照波高の変化と対応しており、波向情報Ｗｄの変化が少ないときに参照波高が高く、波向情報Ｗｄの変化が大きいときに参照波高が低くなり、波向情報Ｗｄの変化が参照波高に対して大きい相関を持っていること等が、発見された。
【００５９】
また、波長情報Ｗｌが参照波高に対応しており、波長情報Ｗｌが大きいときに参照波高が高く、波長情報Ｗｌが小さいときに参照波高が低くなりやすく、波長情報Ｗｌも参照波高に対して大きい相関を持っていることも、発見された。
【００６０】
本発明のレーダ波浪観測装置は、このような波浪情報（波向情報Ｗｄ、演算波高情報Ｗｈ、波長情報Ｗｌ、波速情報Ｗｖｃ）と参照波高との関連や、さらに、波長情報Ｗｌや波速情報Ｗｖｃに基づく海面反射の状態を利用して、演算波高を、参照波高に近づけるように波高補正処理を行って、観測波高の精度を向上したものである。
【００６１】
図３は、本発明の第１の実施の形態に係る波高補正処理器３０の構成を示すブロック図である。
【００６２】
図３において、波高補正処理器３０には、波浪演算処理器２０から波向情報Ｗｄ、演算波高Ｗｈ、波長情報Ｗｌ、波速情報Ｗｖｃが、所定時間毎（例えば、２分間隔）に入力される。
【００６３】
波向変化信号導出手段３１は、波向情報Ｗｄを順次受けて、この波向情報Ｗｄの所定期間の平均値と最新の波向情報との差をとって、その差の絶対値を平均化した平均化波向変化信号ΔＷｄａｖを得る。
【００６４】
この波向変化信号導出手段３１を、図３とともに、図４、図５を参照して説明する。第１平均処理回路３０１は、２分間隔で入力される波向情報Ｗｄの１５個のデータを移動平均して出力する。その時々の最新の平均出力ができるように、移動平均に使うデータは過去１４個のデータとそのときのデータ１個である。
【００６５】
この第１平均処理回路３０１での平均化処理は、０度から３６０度に亘る角度データをベクトル合成で行う。波向情報Ｗｄの角度θｄを、Ｙ軸を基準角度０度として、Ｘ軸成分とＹ軸成分に分け、Ｘ軸側をｓｉｎ（θｄ）、Ｙ軸側をｃｏｓ（θｄ）とする。連続的に得られる平均処理に使用する１５個の波向情報の角度θｄから得る、各Ｘ軸成分を加算して加算値ΣＸを得、各Ｙ軸成分を加算して加算値ΣＹを得る。この加算値ΣＸ、ΣＹから合成角度θｇ（＝ａｔａｎ（ΣＹ／ΣＸ））を得る。この合成角度θｇは、図示されていないが、加算値ΣＸ、ΣＹの正負によって、種々の象限に存在することになる。なお、ａｔａｎは、アークタンジェントを表す。また、加算値ΣＸが０になったときは演算エラーを防止するために、正の０に近い値、例えば０．０００００１に置き換える。
【００６６】
波向情報の平均した角度θｄａｖを得るために、合成角度θｇを得た加算値ΣＸの極性が正であれば、角度θｄａｖ＝９０度−θｇとし、その加算値ΣＸの極性が負であれば、角度θｄａｖ＝２７０度−θｇとする。この処理を、新しい波向情報Ｗｄの入力毎に行うことで、移動平均処理とする。
【００６７】
この第１平均処理回路３０１での移動平均処理を、図４を参照して具体例で説明する。この移動平均処理は１５個の波向情報Ｗｄについて行われるが、説明を簡単にするために、ここでは２個の波向情報Ｗｄ１、Ｗｄ２の場合を例にする。２個の波向情報Ｗｄ１、Ｗｄ２の角度θｄ１、θｄ２を、３０度及び３１０度とする。
【００６８】
角度θｄ１のＸ軸成分ｘ１＝ｓｉｎ（３０）＝０．５、Ｙ軸成分ｙ１＝ｃｏｓ（３０）＝０．８６６０２５であり、角度θｄ２のＸ軸成分ｘ２＝ｓｉｎ（３１０）＝−０．７６６０４４、Ｙ軸成分ｙ２＝ｃｏｓ（３１０）＝０．６４２７８８である。加算値ΣＸ、ΣＹを用いて、合成角度θｇを求めると、θｇ＝ａｔａｎ（ΣＹ／ΣＸ）＝ａｔａｎ（１．５０８８１３／−０．２６６０４４）＝−８０度、となる。このときの加算値ΣＸの極性は負であるから、平均した波向情報Ｗｄａｖの角度θｄａｖは、３５０度（＝２７０度−（−８０度））となる。
【００６９】
減算回路３０２で、そのときの波向情報Ｗｄの角度θｄから平均角度θｄａｖを減算して、波向変化値を得る。その波向変化値は、角度で示されるが、減算回路３０２での減算処理によって正負の両極性になっているので、次の波向１８０度処理のために絶対値変換回路３０３で絶対値の角度に変換する。
【００７０】
波向１８０度処理回路３０４では、２分間隔で得られる波向変化値をその角度値に関係なく、連続的に数値処理できるように、波向変化値を１８０度内に納めるための角度変換処理を行う。この角度変換処理は、図５に示すように、波向１８０度処理回路３０４に入力される波向変化値が、０度以上から１８０度未満の範囲はそのまま出力し、１８０度以上から３６０度未満の範囲では（３６０度−波向変化値）に変換して、第２平均処理回路３０５に出力する。この波向１８０度処理によって、波向変化値が０度から３６０度側へ、あるいは３６０度側から０度側へ変化する場合にも、第２平均処理回路３０５での平均処理を容易に行うことができる。
【００７１】
第２平均処理回路３０５は、波向１８０度処理回路３０４から入力される波向変化値を移動平均する。この移動平均は、過去の２９個の波向変化値と最新の１個の波向変化値を平均するものであり、ばらつきを抑えその時々の最新の平均値を、平均化波向変化信号ΔＷｄａｖとして出力する。
【００７２】
補正演算手段３２は、演算波高情報Ｗｈを、平均化波向変化信号ΔＷｄａｖに応じて、その平均化波向変化信号ΔＷｄａｖが小さいときに高くなり、その平均化波向変化信号ΔＷｄａｖが大きいときに低くなるように演算し、その演算された結果を回帰補正手段によって回帰補正して出力する。補正演算手段３２は、角度リミッタ３０６、べき乗回路３０７、除算回路３０８、第１回帰補正回路３０９、第２回帰補正回路３１０を有している。
【００７３】
角度リミッタ３０６は、入力される平均化波向変化信号ΔＷｄａｖを、その後の処理のために、大きくなりすぎたりあるいは小さくなりすぎることがないように一定範囲内に制限する。この角度リミッタの制限値は、例えば上限値が５０°、下限値を３°とする。
【００７４】
べき乗回路３０７は、角度リミッタを通過した平均化波向変化信号ΔＷｄａｖを所定のべき指数βでべき乗し、波向補正係数Ａｃを出力する。長期間にわたっての観測結果によると、波向変化と超音波波高計等による参照波高とは、波向変化を所定のべき指数βでべき乗した場合に相関がよくなり、相関係数が高くなることが確認された。べき乗回路３０７によるべき乗処理は、波向変化と参照波高との相関係数が高くなることに基づいている。このべき指数は、０．４〜１未満でよく、１つの実施例としては０．５〜０．７が特に好適であった。
【００７５】
除算回路３０８では、演算波高情報Ｗｈを、べき乗回路３０７からの波向補正係数Ａｃで除算する。本発明において、この除算は、長期間にわたって行った観測結果により、全体としてみれば参照波高が高いときに演算波高情報Ｗｈが参照波高に相応して高くならず、参照波高が低いときに演算波高情報Ｗｈが参照波高に相応して低くならない傾向があることと、波向情報Ｗｄの変化が参照波高の変化と対応しており、波向情報Ｗｄの変化が少ないときに参照波高が高く、波向情報Ｗｄの変化が大きいときに参照波高が低くなり、波向情報Ｗｄの変化が参照波高に対して大きい相関を持っていることの発見に基づいて、行われている。
【００７６】
この除算回路３０８での除算結果（＝Ｗｈ／Ａｃ）を、更に参照波高に合わせるように、回帰補正手段によって、回帰処理を行う。この実施の形態では、回帰補正手段として、一次回帰処理（ｙ＝ａｘ＋ｂ）を行う第１回帰補正回路３０９と第２回帰補正回路３１０を設けている。この第１、第２回帰補正回路３０９、３１０の回帰係数ａ，ｂは異なる係数ａ１，ｂ１，ａ２，ｂ２に設定されている。それらの回帰係数は、海面反射状態や、波向変化状況別に応じて観測に基づいて決定されている。この例では、２つの回帰補正回路を設けているが、その他の数の回帰補正回路を設けてもよい。
【００７７】
選択手段３３は、第１、第２回帰補正回路３０９，３１０の出力を、海面反射状態や、波向変化状況に応じて切り替えて出力するものである。この選択手段は、切替回路３１１と、海面反射検出回路３１３と、比較器３１４を有している。
【００７８】
海面反射検出回路３１３は、波浪演算処理器２０から出力される波長情報Ｗｌと波速情報Ｗｖｃとを受けて、波長情報Ｗｌに基づく理論波速Ｗｖｔ（式６を参照）と波速情報Ｗｖｃとの比から海面反射検出信号Ｓｉを得る。この海面反射信号Ｓｉは、海面反射が強いときには小さくなって数値１に近い値を示し、海面反射が弱くなるほど大きな数値（例えば、２５）を示すようになる。なお、この海面反射検出信号Ｓｉの形成手法については、特許第２，５９７，０２７号に記載されている。
【００７９】
比較器３１４は、海面反射検出信号Ｓｉと平均化波向変化信号ΔＷｄａｖが入力される。そして、海面反射検出信号Ｓｉを所定範囲を定める２つの所定閾値（例えば、０．９〜１．２）と比較し、且つ絶対値にされている平均化波向変化信号ΔＷｄａｖを所定閾値（例えば、０．０７、但し前段階で１／１００に処理している）と比較する。海面反射検出信号Ｓｉが所定範囲内（２つの閾値の間）にあり、且つ平均化波向変化信号ΔＷｄａｖが所定閾値以下であるときに、第１回帰補正回路３０９の出力を選択するように、切替回路３１１に選択信号を印加する。それ以外のときは、第２回帰補正回路３１０の出力を選択する。
【００８０】
即ち、波向変化が少なく、かつ海面反射が強いときに第１回帰補正回路３０９の出力が補正波高として用いられる。波向変化が大きいときや、海面反射が弱いときに第２回帰補正回路３１０の出力が補正波高として用いられる。第１、第２回帰補正回路３０９、３１０の回帰係数は、実測データに基づいてそのような波浪状態に合致するような係数に設定されている。
【００８１】
そして、補正波高平均化手段である第３平均処理回路３１２は、第１、第２回帰補正回路３０９、３１０で回帰補正され、切替回路３１１で選択された出力を所定期間だけ平均して補正波高Ｗｈｃを得る。この第３平均処理回路３１２は、２分間隔で入力される回帰補正された１５個のデータを移動平均する。得られた補正波高Ｗｈｃを、出力装置４０へ出力する。
【００８２】
図６は、本発明の第２の実施の形態に係る波高補正処理器３０Ａの構成を示すブロック図である。この第２の実施の形態においては、図３の第１の実施の形態におけるように波向情報Ｗｄの変化に応じて演算波高Ｗｈを補正することに加えて、波長Ｗｌに応じて補正する手段を付加することにより、さらに補正波高の精度を向上するものである。このことは、長い期間での実測データに基づいて、波長Ｗｌが参照波高に対応しており、波長Ｗｌが大きいときに参照波高が高く、波長Ｗｌが小さいときに参照波高が低くなり、波長Ｗｌも参照波高に対して大きい相関を持っていることが確認されたことに基づいている。
【００８３】
図６において、波高補正処理器３０Ａには、図３と同様に、波浪演算処理器２０から波向情報Ｗｄ、演算波高Ｗｈ、波長情報Ｗｌ、波速情報Ｗｖｃが、所定時間毎（例えば、２分間隔）に入力される。
【００８４】
図６の波高補正処理器３０Ａにおいては、除算回路３０８での除算出力を、乗算回路３１５による乗算処理を行ってから、第１回帰補正回路３０９に供給している点と、乗算回路３１５に乗算係数として供給する波長補正係数Ｌｃを発生するための波長信号導出手段３４とを備えている。その他の構成は、図３の波高補正処理器３０と同様であるので、対応する構成要素には同じ符号を付して再度の説明を省略する。
【００８５】
図６において、波長信号導出手段３４は、波浪演算処理器２０からの波長情報Ｗｌが入力され、これを波長リミッタ３１８で最大及び最小を規定値に制限して補正の効き方を調停した波長補正係数Ｌｃを導出し、この波長補正係数Ｌｃを乗算回路３１５に供給する。
【００８６】
この波長リミッタ３１８は、最大のみを規定するものでもよく、その最大の既定値は波がうねり波になったときの誤差を避けるようにするために例えば１２０ｍ（係数として１．２）とする。最小の既定値は必ずしも設ける必要はないが、演算上の安全などのために、設定してもよい（例えば１ｍ、係数として０．０１）。
【００８７】
なお、波長補正係数Ｌｃは実際には、波長情報Ｗｌに所定の係数を乗じているが、この係数は第１回帰補正回路３０９での回帰係数に吸収できるので、ここでは煩雑さを避けるために省略している。
【００８８】
波長補正係数Ｌｃで補正された乗算回路３１５の出力は、第１回帰補正回路３０９で回帰補正される。この第１回帰補正回路３０９での回帰式とその回帰係数は、当然に波長補正された値に適合したものとなっている。この回帰式は、やはり一次回帰式（ｙ＝ａ＋ｂｘ）を用いることができる。また、除算回路３０８の出力は直接に第２回帰補正回路３１０に供給される。
【００８９】
波長情報Ｗｌの精度が良好であるときには、波向き補正係数Ａｃ及び波長補正係数Ｌｃによる補正を行った第１回帰補正回路３０９の出力を採用し、波長情報Ｗｌの精度が得られない状況のときには、波向き補正係数Ａｃのみによる補正を行った第２回帰補正回路３０９の出力を採用する。
【００９０】
その選択は、比較器３１４の出力に応じて、切替回路３１１の切替により行われる。したがって、良好な海面反射が得られ波長の精度が良いかどうかの判断は、図３におけると同様に海面反射検出回路３１３からの海面反射検出信号Ｓｉと平均化波向き変化信号Ｗｄａｖにしたがって行われる。
【００９１】
このように、波高補正処理器３０Ａでは、補正演算手段３２において、波浪演算処理器２０から順次出力される演算波高情報Ｗｈを、平均波向変化信号ΔＷｄａｖに応じて、その平均波向変化信号ΔＷｄａｖが小さいときに高くなり、その平均波向変化信号ΔＷｄａｖが大きいときに低くなるように演算する。さらにこの演算された結果を波長補正係数Ｌｃに応じて、その波長補正係数Ｌｃが大きいときに大きくなり、その波長補正係数Ｌｃが小さいときに小さくなるように演算して出力する。
【００９２】
したがって、演算波高情報Ｗｈにそれぞれ相関を有する波向き補正係数Ａｃ及び波長補正係数Ｌｃで順次補正されるから、波高補正処理器３０Ａから出力される補正波高Ｗｈｃの精度はさらに向上される。
【００９３】
図７は、本発明の第３の実施の形態に係る波高補正処理器３０Ｂの構成を示すブロック図である。この第３の実施の形態においては、図６の第２の実施の形態におけると同様に、波向情報Ｗｄの変化に応じて演算波高Ｗｈを補正することに加えて、波長情報Ｗｌに応じて補正する手段を付加することにより、さらに補正波高の精度を向上するものである。
【００９４】
この図７の第３の形態においては、波長補正係数Ｌｃを得るための波長に関する情報を、波浪演算処理器２０からの波長情報Ｗｌに代えて、別の観測装置などからの周期情報Ｗｔに基づいて得るようにしている。
【００９５】
周期情報Ｗｔは波長との間に特定の変換式に従う関係があるから、周期情報Ｗｔが海面反射の状態などに影響されずに継続して精度よく安定に得られれば、波向き補正係数Ａｃ及び波長補正係数Ｌｃでの順次補正を常に行えるから、波高補正処理器３０Ｂから精度の向上した補正波高Ｗｈｃが継続して得られる。
【００９６】
図７において、波高補正処理器３０Ｂには、図３や図６とは異なり、波浪演算処理器２０から波向情報Ｗｄ、演算波高情報Ｗｈが、所定時間毎（例えば、２分間隔）に入力されるとともに、図８のように、別に設けられた波浪周期入力装置５０からの周期情報Ｗｔが入力される。なお、図８では、波長情報Ｗｌ、波速情報Ｗｖｃも波高補正処理器３０Ｂに入力されるように表現されているが、これは次の実施の形態の説明にも兼用させるためのものである。
【００９７】
図７の波高補正処理器３０Ｂにおいては、除算回路３０８での除算出力を、乗算回路３１５による乗算処理を行ってから、第１回帰補正回路３０９に供給しており、また、乗算回路３１５に乗算係数として供給する波長補正係数Ｌｃを発生するための波長信号導出手段３４を備えている。
【００９８】
図７において、波長信号導出手段３４は、周期情報Ｗｔが入力され、周期／波長変換回路３１６で入力された周期情報Ｗｔを波長情報Ｗｌに変換する。この周期情報Ｗｔから波長情報Ｗｌへの変換は、変換式「Ｗｌ＝１．５６Ｗｔ^２」にしたがって行う。この変換式は、波に関する変換式として知られており、淵秀隆、松本次男、斉藤晃著「海の波」、地人書館、Ｐ３、に記載されている。変換された波長情報Ｗｌは波長リミッタ３１８で最大及び最小を規定値に制限して補正の効き方を調停した波長補正係数Ｌｃを導出し、この波長補正係数Ｌｃを乗算回路３１５に供給する。
【００９９】
周期情報Ｗｔを得る波浪周期入力装置５０は、精度よく周期情報Ｗｔが得られる観測装置であればよい。例えば、レーダ１０との組み合わせ（セット）で考えるならば、レーダ１０の近傍に設置されたペンシルビームを照射し反射波を受信するレーダを用いる。ペンシルビームによる反射波の時間的変化を用いて、波の周期情報を得ることができる。また、海面にブイを浮かべ、そのブイに搭載した速度計や加速度計のデータを用いて、波の周期情報を得ることができる。
【０１００】
また、波浪周期入力装置５０は、目視観測によって得た周期情報Ｗｔを出力するようにしてもよい。目視による波浪周期観測は、見分けやすい水面の泡や浮遊物などを目標とし、その目標物が始めの波の山から次の波の山に来るまでの時間を測ることによって得られる。周期は通常一定の値を持っていることはほとんどないのではっきりした大きめの波をいくつか（普通は１０〜２０波）選んで観測し、その平均値を採る。
【０１０１】
図７の波高補正処理器３０Ｂでは、周期情報Ｗｔが外部から継続して得られるから、図６の選択手段３３は不要であり、また第２回帰補正回路３１０も削除できる。その他の構成は、図３や図６の波高補正処理器３０、３０Ａと同様であるので、対応する構成要素には同じ符号を付して再度の説明を省略する。
【０１０２】
したがって、図７の波高補正処理器３０Ｂでは、乗算回路３１５は、除算回路３０８からの信号、即ち演算波高情報Ｗｈを波向き補正係数Ａｃで除算し波向き補正された信号を、波長補正係数Ｌｃでさらに補正する。したがって、演算波高情報Ｗｈにそれぞれ相関を有する波向き補正係数Ａｃ及び波長補正係数Ｌｃで、常時順次補正するから、波高補正処理器３０Ａから精度が向上された補正波高Ｗｈｃが常に継続して得られる。
【０１０３】
図９は、本発明の第４の実施の形態に係る波高補正処理器３０Ｃの構成を示すブロック図である。この第４の実施の形態においては、図６の第２の実施の形態における波高補正処理器３０Ａに、外部から周期情報Ｗｔが得られる場合にも対応できるように、構成したものである。即ち、図６の波長信号導出手段３４に図８の第３の実施の形態における周期／波長変換回路３１６と切替回路３１７を設けたものである。
【０１０４】
その切替回路３１７は、外部から周期情報Ｗｔが得られる場合には周期／波長変換回路３１６で変換された波長情報を通過させ、周期情報Ｗｔが得られない場合には波長情報Ｗｌを通過させる。どちらを通過させるかの切替は、切替信号ＣＳによって行える。変換された波長情報を通過させるとき切替回路３１１は第１回帰補正回路３０９の出力を選択する。このように選択されるように、切替信号ＣＳによって図のように比較器３１４を制御したり、切替回路３１１を直接切り替えるようにする。
【０１０５】
切替回路３１７、切替回路３１１の切替以外の構成は、図６及び図７の波高補正処理器３０Ａ、３０Ｂにおける構成と同様である。
【０１０６】
したがって、図９の波高補正処理器３０Ｃでは、波向き補正係数Ａｃで除算され波向き補正された信号を、波浪演算処理器２０からの波長情報Ｗｌに基づく波長補正係数Ｌｃでさらに補正して、補正波高Ｗｈｃの精度はさらに向上される。そして、外部から波長周期情報Ｗｔが得られる場合には、波長補正係数Ｌｃで常時補正するから、精度が向上された補正波高Ｗｈｃが常に継続して得られる。
【０１０７】
また、波浪演算処理器２０として、図１０の波浪演算処理器を用いることができる。この図１０の波浪演算処理器は、レーダ１０で海面反射信号を取得し、レーダ信号集録手段６１に連続する多数スキャン（例えば、３２スキャン）のレーダ信号を記録する。次に、３次元ＦＦＴ手段６２で３２スキャン分のレーダ信号を極座標から直角座標に変換し、３次元ＦＦＴ処理を行い、３次元スペクトラムＩ（ｋ、ω）を得る。次に、波浪スペクトル推算手段６３において、計算された３次元スペクトラムＩ（ｋ、ω）を、波の理論式である分散関係式ω^２＝ｇｋに当てはめることによりフィルタリングし、雑音を除去して、本来の波に関する３次元スペクトラムＦ（ｋ、ω）だけを抽出する。そして、シーステート解析手段６４で、抽出された３次元スペクトラムＦ（ｋ、ω）を用いて、波向情報Ｗｄ、波高情報Ｗｈ、波長情報Ｗｌ、波速情報Ｗｖｃの波浪情報を算出する。この波浪演算処理器２０として、非特許文献１に開示されたレーダ波浪測定装置を用いることができる。
【０１０８】
【発明の効果】
本発明のレーダ波浪観測装置によれば、レーダの海面反射信号から波浪演算処理して得た演算波高を、他の波浪演算処理結果（波向、波長、波速）を利用して補正し、超音波波高計等で測定した参照波高に精度良く合わせることができる。これにより、防波堤、護岸、海岸堤防等の構造物設計や船舶の安全並びに効率的運用等に寄与するとともに、海上管制などの有効な運用が可能になる。
【０１０９】
また、波向変化値が、波高値に対する相関が大きいことに基づいて、演算波高を、平均化波向変化信号が小さいときに高くなり、その平均化波向変化信号が大きいときに低くなるように演算し、その演算された結果を回帰補正手段によって回帰補正して出力するから、精度の良い観測波高値を得ることが出来る。
【０１１０】
また、補正演算手段は、回帰係数の異なる複数の回帰補正手段を持ち、海面反射検出信号及び波向変化信号の大きさに応じて、適切な回帰補正手段を選択するから、海面の状況により適した波高補正を行うことが出来る。
【０１１１】
演算波高を、波向変化信号が小さいときに高くなり、その波向変化信号が大きいときに低くなるように演算し、さらにこの演算された結果を波長補正係数に応じて、その波長補正係数が大きいときに大きくなり、その波長補正係数が小さいときに小さくなるように演算して出力する。これにより、演算波高にそれぞれ相関を有する波向き補正係数及び波長補正係数で順次補正されるから、波高補正処理器から出力される補正波高の精度はさらに向上される。
【０１１２】
また、波高の補正を他の周辺機器を必要とせず、レーダ波浪観測装置を安価に構成でき、その設置も容易になる。また、周期情報を他の装置や目視観測によって得られる場合には、より精度の向上した補正波高を海面の状態によらす、継続して得ることができる。
【図面の簡単な説明】
【図１】本発明のレーダ波浪観測装置の全体構成を示す図。
【図２】本発明に用いる波浪演算処理器のブロック図。
【図３】本発明の第１の実施の形態に係る波高補正処理器のブロック図。
【図４】波向平均処理方法を説明ずる図。
【図５】波向１８０度処理を説明する図。
【図６】本発明の第２の実施の形態に係る波高補正処理器のブロック図。
【図７】本発明の第３の実施の形態に係る波高補正処理器のブロック図。
【図８】本発明のレーダ波浪観測装置の他の全体構成を示す図。
【図９】本発明の第４の実施の形態に係る波高補正処理器のブロック図。
【図１０】本発明に用いる、他の波浪演算処理器のブロック図。
【符号の説明】
１０ レーダ
２０ 波浪演算処理器
２１ レーダ信号集録手段
２２ レーダ干渉検出手段
２３ ２次元演算手段
２４ 平均化手段
２５ 波浪スペクトル推算手段
２６ シーステート解析手段
３０ 波高補正処理器
３１ 波向変化信号導出手段
３０１ 第１平均処理回路
３０２ 減算回路
３０３ 絶対値変換回路
３０４ 波向１８０度処理回路
３０５ 第２平均処理回路
３２ 補正演算手段
３０６ 角度リミッタ
３０７ べき乗回路
３０８ 除算回路
３０９ 第１回帰補正回路
３１０ 第２回帰補正回路
３１５ 乗算回路
３３ 選択手段
３１１ 切替回路
３１２ 第３平均処理回路
３１３ 海面反射検出回路
３１４ 比較器
３４ 波長信号導出手段
３１６ 周期／波長変換回路
３１７ 切替回路
３１８ 波長リミッタ
４０ 出力装置
５０ 波浪周期入力装置
６１ レーダ信号集録手段
６２ ３次元ＦＦＴ手段
６３ 波浪スペクトル推算手段
６４ シーステート解析手段
Ｗｄ 波向情報
Ｗｈ 波高情報
Ｗｌ 波長情報
Ｗｖｃ 波速情報
Ｗｈｃ 補正波高
Ｗｔ 周期情報
ΔＷｄａｖ 平均化波向変化信号
Ａｃ 波向補正係数
Ｓｉ 海面反射検出信号
Ａｃ 波向補正係数
Ｌｃ 波長補正係数[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radar wave observation apparatus that collects radar sea clutter signals and applies Fourier transform processing to observe wave characteristics such as wavelength, wave speed, wave direction, and wave height.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, wave characteristics such as wavelength, wave speed, wave direction, wave height and the like have been measured using a pulse radar and a radar reflection signal from the sea surface.
[0003]
By applying a three-dimensional Fourier transform to a large number of consecutive radar images (eg, 32) and applying a theoretical wave equation (dispersion relational equation) to the conversion result, noise is removed and 3 Non-Patent Document 1 discloses extracting a three-dimensional spectrum and calculating wave information such as wavelength, wave velocity, wave direction, and wave height using the extracted three-dimensional spectrum.
[0004]
In addition, a two-dimensional cross spectrum is obtained from two consecutive scan radar images, and the spectrum is filtered by a theoretical wave equation (wave velocity relational equation) to calculate wave information such as wavelength, wave velocity, wave direction and wave height. Is shown in Patent Document 1.
[0005]
[Non-Patent Document 1]
[ESTIMATION OF SEA STATE DIRECTIONAL SPECTRA BY USING MARINE RADAR IMAGING OF SEA SURFACE], Proceedings of ETCE / OMAE 2000 February14-17,2000, NewOrleans, LA
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-21680
[0006]
[Problems to be solved by the invention]
However, in the conventional radar wave measurement devices of Patent Document 1 and Non-Patent Document 1, the wave height obtained by the calculation depends on the state of the measurement sea area, etc. In some cases, the difference from the wave height measured by a sonic wave height meter increases.
[0007]
Therefore, the present invention obtains a radar image from a radar reflection signal from the sea surface, calculates the wave information including the wave height by calculating the radar image and calculating the wave information (hereinafter referred to as the calculated wave height). Using other wave information obtained from the wave calculation processor or other wave information from another wave observation device, etc., the wave height (hereinafter referred to as reference wave height) measured with an ultrasonic wave height meter etc. as a reference An object of the present invention is to provide a radar wave observation device that performs wave height correction processing so as to be close to each other and improves the accuracy of the observed wave height (hereinafter, observed wave height; corrected wave height).
[0008]
[Means for Solving the Problems]
A radar wave observation device according to claim 1 obtains a radar image from a radar reflection signal from the sea surface, Fourier transforms the radar image, and applies a theoretical wave equation to the conversion result, thereby obtaining a spectrum relating to the wave. Based on the wave direction information that is extracted, and uses the extracted spectrum to calculate wave information including wave direction information and wave height information, and wave direction information that is sequentially output from the wave calculation processor based on a predetermined direction. The wave direction change signal deriving means for obtaining the wave direction change signal representing the amount of change in the wave direction information, and the wave height signal corresponding to the wave height information sequentially output from the wave operation processor according to the wave direction change signal. A wave height correction processor comprising: a correction calculation means for calculating and outputting the signal so as to be high when the wave direction change signal is small and low when the wave direction change signal is large; Characterized in that it has a.
[0009]
The radar wave observation device according to claim 2 is the radar wave observation device according to claim 1,
The wave height correction processor further includes correction wave height averaging means for obtaining a correction wave height by averaging the output from the correction calculation means for a predetermined period,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. And the calculated result is subjected to regression correction by the regression correction means and output.
[0010]
The radar wave observation device according to claim 3 is the radar wave observation device according to claim 1 or 2, wherein the correction calculation means has a plurality of regression correction means each having a different regression coefficient as the regression correction means. ,
Further, the sea surface reflection detection means for receiving the wavelength information and the wave speed information sequentially output from the wave calculation processor and obtaining a sea surface reflection detection signal from the ratio of the theoretical wave speed and the wave speed information based on the wavelength information, the sea surface reflection detection Signal and the wave direction change signal are input, the sea surface reflection detection signal is compared with a threshold value defining a predetermined range, the wave direction change signal is compared with a predetermined threshold value, and a selection command signal corresponding to the comparison result is output. And a selection means having a switching means for inputting the selection command signal and switching and outputting the outputs of the plurality of regression correction means in accordance with the selection command signal.
[0011]
The radar wave observation device according to claim 4 is the radar wave observation device according to any one of claims 1 to 3, wherein the correction calculation means includes an angle limiter for limiting the maximum / minimum of the wave direction change signal, and the angle A power means for deriving a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the limiter, a division means for dividing the wave height signal by the wave direction correction coefficient, and division by the division means And a regression correction means for performing regression correction on the output.
[0012]
The radar wave observation apparatus according to claim 5 obtains a radar image from a radar reflection signal from the sea surface, performs Fourier transform on the radar image, and applies a theoretical wave equation to the conversion result, thereby obtaining a spectrum relating to the wave. Based on the wave direction information that is extracted, and uses the extracted spectrum to calculate wave information including wave direction information and wave height information, and wave direction information that is sequentially output from the wave calculation processor based on a predetermined direction. A wave direction change signal deriving means for obtaining a wave direction change signal representing the change amount of the wave direction information,
Wavelength signal deriving means for obtaining a wavelength correction coefficient representing the magnitude of the wavelength;
The wave height signal corresponding to the wave height information sequentially output from the wave arithmetic processor becomes high when the wave direction change signal is small and low when the wave direction change signal is large according to the wave direction change signal. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. And a wave height correction processor configured to include a calculation means.
[0013]
The radar wave observation device according to claim 6 is the radar wave observation device according to claim 5, wherein the wavelength signal deriving means is configured to use the wavelength correction coefficient based on wavelength information sequentially output from the wave calculation processor. It is characterized by obtaining.
[0014]
The radar wave observation device according to claim 7 is the radar wave observation device according to claim 6, wherein the wave height correction processor further averages the output from the correction calculation means for a predetermined period to obtain a correction wave height. Having correction wave height averaging means to obtain,
The wavelength signal deriving means obtains the wavelength correction coefficient based on the wavelength information sequentially output from the wave arithmetic processor,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. Is output after being subjected to regression correction by a regression correction means.
[0015]
The radar wave observation device according to claim 8 is the radar wave observation device according to claim 7, wherein the correction calculation means includes a first regression correction means as the regression correction means, and a first regression correction means. Having a regression coefficient different from the regression coefficient, and having a second regression correction means for performing regression correction on a calculation result obtained by calculating the wave height signal according to the average wave direction change signal,
Further, the sea surface reflection detection means for receiving the wavelength information and the wave speed information sequentially output from the wave calculation processor and obtaining a sea surface reflection detection signal from the ratio of the theoretical wave speed and the wave speed information based on the wavelength information, the sea surface reflection detection The signal and the wave direction change signal are input, the sea surface reflection detection signal is compared with a threshold value that defines a predetermined range, the wave direction change signal is compared with a predetermined threshold value, and the comparison result is within the predetermined range and the predetermined threshold value. Comparison means for selecting the first regression correction means when it is below, and outputting a selection command signal for selecting the second regression correction means otherwise, the selection command signal is inputted, And a switching unit that switches and outputs the outputs of the first and second regression correction units in accordance with the selection command signal.
[0016]
The radar wave observation apparatus according to claim 9 is the radar wave observation apparatus according to claims 7 and 8, wherein the wavelength signal deriving means is obtained from wavelength information sequentially output from the wave arithmetic processor. A wavelength limiter that limits at least the upper limit of the wavelength correction coefficient,
The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, Power means, division means for dividing the wave height signal by the wave direction correction coefficient, multiplication means for multiplying the division output of the division means by the limited wavelength correction coefficient from the wavelength signal deriving means, and multiplication The first regression correction means for performing regression correction to output the multiplication output of the means, and the second regression correction means for performing regression correction to output the division output of the division means.
[0017]
The radar wave observation device according to claim 10 is the radar wave observation device according to claim 5, wherein the wavelength signal deriving means obtains the wavelength correction coefficient based on period information input from the outside. It is characterized by that.
[0018]
The radar wave observation device according to claim 11 is the radar wave observation device according to claim 10, wherein the wave height correction processor further averages the output from the correction calculation means for a predetermined period to obtain a correction wave height. Having correction wave height averaging means to obtain,
The wavelength signal deriving means converts the period information according to a predetermined conversion formula to obtain the wavelength correction coefficient,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. Is output after being subjected to regression correction by a regression correction means.
[0019]
The radar wave observation device according to claim 12 is the radar wave observation device according to claim 11, wherein the wavelength signal deriving means converts the period information into the wavelength correction coefficient according to a predetermined conversion formula. A wavelength conversion unit, and a wavelength limiter that outputs at least an upper limit value of the wavelength correction coefficient from the period / wavelength conversion unit.
The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, Power means, division means for dividing the wave height signal by the wave direction correction coefficient, multiplication means for multiplying the division output of the division means by the limited wavelength correction coefficient from the wavelength signal deriving means, and multiplication And regression correction means for performing regression correction and outputting the multiplication output of the means.
[0020]
The radar wave observation device according to claim 13 is the radar wave observation device according to claim 5, wherein the wavelength signal deriving means is a wavelength correction obtained based on wavelength information sequentially output from the wave operation processor. One of the coefficient and the wavelength correction coefficient obtained based on the period information input from the outside is selected and output.
[0021]
The radar wave observation device according to claim 14 is the radar wave observation device according to claim 13, wherein the wave height correction processor further averages the output from the correction calculation means for a predetermined period to obtain a correction wave height. Having correction wave height averaging means to obtain,
The wavelength signal deriving means is either a wavelength correction coefficient obtained from wavelength information sequentially output from the wave calculation processor, or a wavelength correction coefficient obtained by converting the period information according to a predetermined conversion formula. To select and output,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. Is output after being subjected to regression correction by a regression correction means.
[0022]
The radar wave observation device according to claim 15 is the radar wave observation device according to claim 14, wherein the correction calculation means includes a first regression correction means as the regression correction means, and a first regression correction means. Having a regression coefficient different from the regression coefficient, and having a second regression correction means for performing regression correction on a calculation result obtained by calculating the wave height signal according to the average wave direction change signal,
Further, the sea surface reflection detection means for receiving the wavelength information and the wave speed information sequentially output from the wave calculation processor and obtaining a sea surface reflection detection signal from the ratio of the theoretical wave speed and the wave speed information based on the wavelength information, the sea surface reflection detection The signal and the wave direction change signal are input, the sea surface reflection detection signal is compared with a threshold value that defines a predetermined range, the wave direction change signal is compared with a predetermined threshold value, and the comparison result is within the predetermined range and the predetermined threshold value. Comparison means for selecting the first regression correction means when it is below, and outputting a selection command signal for selecting the second regression correction means otherwise, the selection command signal is inputted, And switching means for switching and outputting the outputs of the first and second regression correction means according to the selection command signal, and the wavelength signal deriving means converts the period information according to a predetermined conversion formula. And if you have selected a wavelength correction coefficient characterized by having a selection means adapted to select the first corrected return means.
[0023]
The radar wave observation device according to claim 16 is the radar wave observation device according to claim 14 or 15, wherein the wavelength signal deriving means converts the period information into a wavelength correction coefficient according to a predetermined conversion formula. / Wavelength conversion means, and a wavelength correction coefficient obtained from the wavelength information and a wavelength correction coefficient from the period / wavelength conversion means are input, and one of these wavelength correction coefficients is selected and output according to the switching signal. Means, and a wavelength limiter for limiting and outputting at least an upper limit value of the wavelength correction coefficient from the switching means,
The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, Power means, division means for dividing the wave height signal by the wave direction correction coefficient, multiplication means for multiplying the division output of the division means by the limited wavelength correction coefficient from the wavelength signal deriving means, and multiplication The first regression correction means for performing regression correction to output the multiplication output of the means, and the second regression correction means for performing regression correction to output the division output of the division means.
[0024]
The radar wave observation device according to claim 17 is the radar wave observation device according to any one of claims 1 to 16, wherein the wave direction change signal deriving means sequentially receives the wave direction information and receives the wave direction for a predetermined period. First wave direction average processing means for outputting an average value of information, subtraction means for taking a difference between the average value output of the first wave direction average processing means and the latest wave direction information, and output of the subtraction means Absolute value conversion means for converting to absolute value and the output of this absolute value conversion means, and those passing from 0 degree to less than 180 degrees are passed as they are, and those from 180 degrees to less than 360 degrees are subtracted from 360 degrees and output. And a wave direction average processing means for averaging the outputs of the wave direction 180 degree processing means for a predetermined period and outputting the averaged wave direction change signal.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an overall configuration of a radar wave observation apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram of a wave arithmetic processor used in the present invention. FIG. 3 is a block diagram of the wave height correction processor according to the first embodiment of the present invention. FIG. 4 is a diagram for explaining the wave direction averaging processing method, and FIG. 5 is a diagram for explaining the wave direction 180 degree processing.
[0026]
As shown in FIG. 1, the radar wave observation apparatus according to the present invention obtains wave information of wave direction information Wd, wave height information Wh, wavelength information Wl, and wave speed information Wvc based on a sea surface reflection signal obtained by a pulse radar 10 for ships. A wave calculation processor 20 obtained by calculation and a wave height correction processor 30 that corrects the wave height information Wh obtained by calculation using the wave direction information Wd, wavelength information Wl, and wave speed information Wvc to obtain a corrected wave height Whc. Has been. The pulse radar 10 is mounted on land or a ship and irradiates a sea area where waves should be observed. Reference numeral 40 denotes an output device that displays and stores the corrected wave height Whc and other information. Each means and each circuit of the wave calculation processor 20 and the wave height correction processor 30 will be described with individual circuit configurations, but can be similarly realized by software processing using a computer.
[0027]
2, the radar signal acquisition unit 21 records the radar data acquired by the radar 10 for two consecutive scans. The radar data is subjected to A / D conversion after amplifying and detecting the received sea surface reflection signal, sampling at a period matching the required distance resolution. Hereinafter, the wave direction information Wd, the wave height information Wh, the wavelength information Wl, and the wave speed information Wvc may be simply referred to as the wave direction Wd, the wave height Wh, the wavelength Wl, and the wave speed Wvc.
[0028]
The radar interference detection means 22 detects whether or not the radar data recorded in the radar signal acquisition means 21 has received radio wave interference from other radio sources such as other radars and radar beacons. When interference is received, the radar data of the scan is discarded, and the continuous two-scan radar data that is not subjected to the interference is supplied to the two-dimensional calculation means 23.
[0029]
There are various detection methods for the presence or absence of radio wave interference in the radar interference detection means 22, but as one method, it can be regarded as interference when the data level exceeds the normal level. For example, when the data in the distance direction of polar coordinates are added and the normal signal level is exceeded, it is determined as interference. For example, when an 8-bit A / D converter is used, the normal signal level takes a value of 0 to 255, but a value around 64.
[0030]
The two-dimensional calculation means 23 receives two consecutive scans of radar data that are not subject to radio wave interference. First, since the reception level is higher as the distance is shorter, the intensity in the distance direction is corrected, and the radar data is changed from polar coordinates to orthogonal coordinates. Convert coordinates. In order to determine the sea surface monitoring range, the radar data is cut into, for example, a square shape (side length D). This cutting may be performed at the time of coordinate conversion or before that.
[0031]
The coordinate-converted radar data is subjected to two-dimensional Fourier transform (hereinafter referred to as two-dimensional FFT) for each scan to obtain a two-dimensional Fourier transform value F (k, l).
[0032]
[Formula 1]

Here, f (n, m) is radar data, and F (k, l) is a spatial spectrum. N and m are coordinate values, and k and l are wave numbers.
[0033]
Next, the cross spectrum P between the two-dimensional FFT values for the radar data of successive scans _C Find (k, l).
[0034]
[Formula 2]

[0035]
Next, this two-dimensional cross spectrum P _C An amplitude spectrum Sa and a phase spectrum Sφ for each point of (k, l) are calculated. Cross spectrum P at each point _C Since (k, l) is expressed by a complex number, if its real part is Re and its imaginary part is Im, it is expressed by Expression (3) and Expression (4).
[0036]
[Formula 3]

[0037]
[Formula 4]

It becomes. Note that atan represents an arc tangent.
[0038]
In this way, the cross spectrum P between the two-dimensional FFT values for the continuous two-scan radar data. _C (K, l) and its amplitude spectrum Sa and phase spectrum Sφ are obtained.
[0039]
In the averaging means 24, the two-dimensional cross spectrum P supplied from the two-dimensional calculation means 23. _C The average value of the amplitude spectrum Sa and the phase spectrum Sφ is obtained by adding and dividing the amplitude spectrum Sa and the phase spectrum Sφ for each point of (k, l) by a predetermined number N (for example, 32 times). This averaging process is performed while inputting continuous two-scan data. Therefore, when there is no radio wave interference, N + 1 scan data is averaged. By this averaging, the two-dimensional cross spectrum P of the amplitude spectrum Sa and the phase spectrum Sφ. _C Since variations in values for each (k, l) are absorbed, the subsequent calculation / analysis is performed stably.
[0040]
In the wave spectrum estimation means 25, first, the averaged two-dimensional cross spectrum P _C The peak value of the amplitude spectrum Sa is obtained from (k, l). When the phase corresponding to the phase spectrum Sφ at the peak point is φ, the calculated wave velocity Wvc is obtained by the equation (5).
[0041]
[Formula 5]

Where D is the side length, k and l are wave numbers on the two-dimensional cross spectrum, and T is the radar scan time.
[0042]
On the other hand, the theoretical wave velocity Wvt determined by the wave velocity relational equation, which is the theoretical equation of the wave, is obtained from equation (6).
[0043]
[Formula 6]

However, Wl is a wavelength.
[0044]
The wave velocity relational expression that determines the theoretical wave velocity is obtained as follows. In general, the wave dispersion relational expression is expressed by Expression (7).
[0045]
[Formula 7]

Where d is the water depth and k _v Is the wave vector and U is the surface flow. As the water depth increases, the term of tanh () disappears, and when U = 0, the dispersion relational expression becomes Expression (8).
[0046]
[Formula 8]

In this dispersion relational expression ω, the general formula of wave velocity Wvt = ω / k _v To eliminate ω, k _v Since = 2π / Wl, equation (6) is obtained.
[0047]
Thus, on the one hand, the calculated wave velocity Wvc is calculated from the phase spectrum Sφ corresponding to the amplitude spectrum of the peak point and the wave number on its two-dimensional cross spectrum, and on the other hand, the theoretical wave velocity Wvt is the wavelength, in other words, the two-dimensional cross Calculated by wave number on the spectrum.
[0048]
Therefore, whether the amplitude spectrum of the peak point and the corresponding phase spectrum Sφ are due to the original wave or noise is determined by whether or not the calculated wave speed Wvc matches the theoretical wave speed Wvt. be able to. The degree of matching is determined as matching if the calculated wave speed Wvc is within ± 10% of the theoretical wave speed Wvt. The calculated wave velocity Wvc at this time is the desired wave velocity. As a result of filtering, when the calculated wave velocity Wvc does not match the theoretical wave velocity Wvt, the amplitude spectrum and phase spectrum at that time are not used because they are not of the original wave.
[0049]
As a result, the amplitude spectrum P of the two-dimensional cross spectrum obtained by calculation. _C The amplitude spectrum Sa and phase spectrum Sφ of (k, l) are filtered by the wave spectrum estimation means 25, and the original wave amplitude spectrum Sa and phase spectrum Sφ are output and supplied to the seastate analysis means 26.
[0050]
The sea state analysis means 26 obtains the center of gravity of the original wave phase spectrum Sφ filtered by the wave spectrum estimation means 25 within the coordinates of ± L around the peak value, and calculates the wavelength Wl and the wave from the center of the phase spectrum. The direction Wd is obtained by the equations (9) and (10), respectively.
[0051]
[Formula 9]

[0052]
[Formula 10]

[0053]
Further, the wave velocity Wvc is calculated for each wave, for example, for a wave having a large amplitude spectrum Sa, based on the corresponding phase spectrum Sφ.
[0054]
Further, the sum W of the amplitude spectrum Sa before being filtered by the wave spectrum estimating means 25 is calculated, and the sum of the peak points of the amplitude spectrum Sa of the two-dimensional cross spectrum and the amplitude spectrum in a predetermined range around it is calculated by the sea state analyzing means 26. S is calculated, and the peak value Wh is obtained by Wh = A + B × {S / (WS)} by a regression equation based on the regression coefficients A and B obtained in advance. When there are a plurality of waves, the sum S1, S2,... Of the amplitude spectrum of each peak point and its surrounding predetermined range is calculated, and each peak value is calculated by the formula Wh1 = A + B × {S1 / ( W−S1−S2...}, And a calculation formula Wh2 = A + B × {S2 / (W−S1−S2...)}. As the wave calculation processor 20, the radar wave measuring device disclosed in Patent Document 1 can be used.
[0055]
Next, in the wave height correction processor 30 of FIG. 1, the wave direction information Wd, the wave height information Wh (hereinafter, the calculated wave height information Wh), the wavelength information Wl, and the wave velocity information Wvc obtained by the wave operation processor 20 are input. The calculated wave height information Wh is corrected to output a corrected wave height Whc (hereinafter, corrected wave height Whc).
[0056]
The correction processing of the calculated wave height information Wh in the wave height correction processor 30 in FIG. 1 includes a phenomenon in which the difference between the reference wave height by the ultrasonic wave height meter or the like and the calculated wave height information Wh increases, and other wave information (wave direction information). Wd, wavelength information Wl, and wave velocity information Wvc) are found based on the discovery of the relationship.
[0057]
Ultrasonic wave height meter transmits ultrasonic pulses from the sea floor toward the sea surface, converts the elapsed time until the pulse is reflected back on the sea surface and returns to the distance, measures the sea level height, Get the wave height. The wave height meter for obtaining the reference wave height is not limited to the ultrasonic wave height meter, and other wave height meters such as a capacity type / resistance type wave height meter, a laser type / radio wave type wave height meter, and the like can be used.
[0058]
Specifically, the correction processing of the calculated wave height information Wh is carried out by measuring the reference wave height for a long period in parallel with the acquisition of the wave information (wave direction information Wd, calculated wave height information Wh, wavelength information Wl, wave speed information Wvc). The reference wave height and the calculated wave height Wh were compared. According to the comparison, there is a case where the reference wave height and the calculated wave height Wh substantially coincide with each other. However, when the reference wave height is high as a whole, the calculated wave height Wh does not increase correspondingly to the reference wave height, and the reference wave height is low. Sometimes, the calculated wave height Wh tends not to be low corresponding to the reference wave height, or the change in the wave direction information Wd corresponds to the change in the reference wave height, and the reference wave height is small when the change in the wave direction information Wd is small. It was discovered that the reference wave height is low when the wave direction information Wd is large and the change in the wave direction information Wd is large, and the change in the wave direction information Wd has a large correlation with the reference wave height.
[0059]
Further, the wavelength information Wl corresponds to the reference wave height, the reference wave height is high when the wavelength information Wl is large, the reference wave height tends to be low when the wavelength information Wl is small, and the wavelength information Wl is also large with respect to the reference wave height. It was also discovered that there is a correlation.
[0060]
The radar wave observation apparatus according to the present invention includes the relationship between such wave information (wave direction information Wd, calculation wave height information Wh, wavelength information Wl, wave speed information Wvc) and reference wave height, and further includes wavelength information Wl and wave speed information Wvc. The wave height correction processing is performed so that the calculated wave height approaches the reference wave height using the state of sea surface reflection based on the above, and the accuracy of the observed wave height is improved.
[0061]
FIG. 3 is a block diagram showing the configuration of the wave height correction processor 30 according to the first embodiment of the present invention.
[0062]
In FIG. 3, wave direction information Wd, calculation wave height Wh, wavelength information Wl, and wave velocity information Wvc are input to the wave height correction processor 30 at predetermined time intervals (for example, every two minutes). .
[0063]
The wave direction change signal deriving means 31 sequentially receives the wave direction information Wd, takes the difference between the average value of the wave direction information Wd for a predetermined period and the latest wave direction information, and averages the absolute value of the difference. The averaged wave direction change signal ΔWdav is obtained.
[0064]
The wave direction change signal deriving means 31 will be described with reference to FIGS. 4 and 5 together with FIG. The first average processing circuit 301 performs a moving average of 15 pieces of data of the wave direction information Wd input at intervals of 2 minutes and outputs the result. The data used for the moving average is the past 14 data and the data at that time so that the latest average output at that time can be performed.
[0065]
The averaging process in the first average processing circuit 301 performs angle data ranging from 0 degrees to 360 degrees by vector synthesis. The angle θd of the wave direction information Wd is divided into an X-axis component and a Y-axis component with the Y-axis as a reference angle of 0 degree, and the X-axis side is sin (θd) and the Y-axis side is cos (θd). Each X-axis component obtained from the angles θd of 15 wave direction information used for the averaging process obtained continuously is added to obtain an added value ΣX, and each Y-axis component is added to obtain an added value ΣY. A composite angle θg (= atan (ΣY / ΣX)) is obtained from the added values ΣX and ΣY. Although not shown in the figure, this combined angle θg exists in various quadrants depending on whether the addition values ΣX and ΣY are positive or negative. Note that atan represents an arc tangent. Further, when the addition value ΣX becomes 0, it is replaced with a value close to positive 0, for example, 0.000001, in order to prevent a calculation error.
[0066]
In order to obtain the average angle θdav of the wave direction information, if the polarity of the addition value ΣX obtained from the combined angle θg is positive, the angle θdav = 90 degrees−θg, and if the polarity of the addition value ΣX is negative. The angle θdav = 270 degrees−θg. This process is performed every time new wave direction information Wd is input, thereby making a moving average process.
[0067]
The moving average process in the first average processing circuit 301 will be described with a specific example with reference to FIG. This moving average process is performed for 15 pieces of wave direction information Wd. In order to simplify the explanation, here, the case of two pieces of wave direction information Wd1 and Wd2 is taken as an example. The angles θd1 and θd2 of the two pieces of wave direction information Wd1 and Wd2 are 30 degrees and 310 degrees.
[0068]
The X-axis component x1 = sin (30) = 0.5 of the angle θd1, the Y-axis component y1 = cos (30) = 0.866025, and the X-axis component x2 = sin (310) = − 0.766044 of the angle θd2. , Y-axis component y2 = cos (310) = 0.642788. Using the addition values ΣX and ΣY to obtain the combined angle θg, θg = atan (ΣY / ΣX) = atan (1.5088813 / −0.266044) = − 80 degrees. Since the polarity of the added value ΣX at this time is negative, the angle θdav of the averaged wave direction information Wdav is 350 degrees (= 270 degrees − (− 80 degrees)).
[0069]
The subtracting circuit 302 subtracts the average angle θdav from the angle θd of the wave direction information Wd at that time to obtain a wave direction change value. The wave direction change value is indicated by an angle. However, since it has both positive and negative polarities by the subtraction processing in the subtraction circuit 302, the absolute value conversion circuit 303 performs absolute value conversion for the next wave direction 180 degree processing. Convert to angle.
[0070]
In the wave direction 180 degree processing circuit 304, an angle conversion for keeping the wave direction change value within 180 degrees so that the wave direction change value obtained at intervals of 2 minutes can be continuously numerically processed regardless of the angle value. Process. In this angle conversion process, as shown in FIG. 5, when the wave direction change value input to the wave direction 180 degree processing circuit 304 is in the range from 0 degree to less than 180 degree, it is output as it is, and from 180 degree to 360 degree. If it is less than the range, it is converted into (360 degrees-wave direction change value) and output to the second average processing circuit 305. By this wave direction 180 degree processing, even when the wave direction change value changes from 0 degree to 360 degrees or from 360 degrees to 0 degrees, the average process in the second average processing circuit 305 is easily performed. be able to.
[0071]
The second average processing circuit 305 performs a moving average of the wave direction change values input from the wave direction 180 degree processing circuit 304. This moving average is an average of the past 29 wave direction change values and the latest one wave direction change value, and suppresses variation, and the latest average value at each time is used as an averaged wave direction change signal ΔWdav. Output as.
[0072]
The correction calculation means 32 increases the calculation wave height information Wh according to the average wave direction change signal ΔWdav when the average wave direction change signal ΔWdav is small and when the average wave direction change signal ΔWdav is large. The calculation is performed so as to decrease, and the calculated result is subjected to regression correction by the regression correction means and output. The correction calculation means 32 includes an angle limiter 306, a power circuit 307, a division circuit 308, a first regression correction circuit 309, and a second regression correction circuit 310.
[0073]
The angle limiter 306 limits the input averaged wave direction change signal ΔWdav within a certain range so as not to become too large or too small for subsequent processing. The limit value of the angle limiter is, for example, an upper limit value of 50 ° and a lower limit value of 3 °.
[0074]
The power circuit 307 powers the average wave direction change signal ΔWdav that has passed through the angle limiter by a predetermined power exponent β, and outputs a wave direction correction coefficient Ac. According to observation results over a long period of time, the correlation between the wave direction change and the reference wave height obtained by an ultrasonic wave height meter, etc., is improved when the wave direction change is raised to the power of a predetermined exponent β, and the correlation coefficient increases. Was confirmed. The power process by the power circuit 307 is based on the fact that the correlation coefficient between the wave direction change and the reference wave height increases. This power index may be less than 0.4 to 1, and 0.5 to 0.7 was particularly suitable as one example.
[0075]
The division circuit 308 divides the calculated wave height information Wh by the wave direction correction coefficient Ac from the power circuit 307. In the present invention, this division is based on the observation results obtained over a long period of time. When the reference wave height is high as a whole, the calculated wave height information Wh does not increase correspondingly to the reference wave height, and the calculated wave height when the reference wave height is low. There is a tendency that the information Wh does not decrease correspondingly to the reference wave height, the change in the wave direction information Wd corresponds to the change in the reference wave height, and the reference wave height is high when the change in the wave direction information Wd is small. The reference wave height is lowered when the change in the direction information Wd is large, and this is performed based on the discovery that the change in the wave direction information Wd has a large correlation with the reference wave height.
[0076]
The regression processing is performed by the regression correction means so that the division result (= Wh / Ac) in the division circuit 308 further matches the reference wave height. In this embodiment, a first regression correction circuit 309 and a second regression correction circuit 310 that perform primary regression processing (y = ax + b) are provided as regression correction means. The regression coefficients a and b of the first and second regression correction circuits 309 and 310 are set to different coefficients a1, b1, a2 and b2. These regression coefficients are determined based on observations according to the state of sea surface reflection and the change in wave direction. In this example, two regression correction circuits are provided, but other numbers of regression correction circuits may be provided.
[0077]
The selection means 33 switches and outputs the outputs of the first and second regression correction circuits 309 and 310 according to the sea surface reflection state and the wave direction change state. This selection means includes a switching circuit 311, a sea surface reflection detection circuit 313, and a comparator 314.
[0078]
The sea surface reflection detection circuit 313 receives the wavelength information W1 and the wave speed information Wvc output from the wave calculation processor 20, and calculates the ratio between the theoretical wave speed Wvt (see Equation 6) based on the wavelength information W1 and the wave speed information Wvc. A sea surface reflection detection signal Si is obtained. The sea surface reflection signal Si becomes smaller when the sea surface reflection is strong and shows a value close to the numerical value 1, and becomes larger as the sea surface reflection becomes weaker (for example, 25). A method for forming the sea surface reflection detection signal Si is described in Japanese Patent No. 2,597,027.
[0079]
The comparator 314 receives the sea surface reflection detection signal Si and the averaged wave direction change signal ΔWdav. Then, the sea surface reflection detection signal Si is compared with two predetermined threshold values (for example, 0.9 to 1.2) that define a predetermined range, and the averaged wave direction change signal ΔWdav that is set to an absolute value is set to a predetermined threshold value (for example, , 0.07, but processed to 1/100 in the previous step). When the sea surface reflection detection signal Si is within a predetermined range (between two threshold values) and the average wave direction change signal ΔWdav is equal to or less than the predetermined threshold value, the output of the first regression correction circuit 309 is selected. A selection signal is applied to the switching circuit 311. In other cases, the output of the second regression correction circuit 310 is selected.
[0080]
That is, when the wave direction change is small and the sea surface reflection is strong, the output of the first regression correction circuit 309 is used as the correction wave height. When the wave direction change is large or when the sea surface reflection is weak, the output of the second regression correction circuit 310 is used as the correction wave height. The regression coefficients of the first and second regression correction circuits 309 and 310 are set to coefficients that match such a wave state based on actual measurement data.
[0081]
Then, the third average processing circuit 312 which is a corrected wave height averaging means performs regression correction by the first and second regression correction circuits 309 and 310, averages the output selected by the switching circuit 311 for a predetermined period, and corrects the corrected wave height. Get Whc. The third average processing circuit 312 performs a moving average of 15 pieces of regression-corrected data input at intervals of 2 minutes. The obtained corrected wave height Whc is output to the output device 40.
[0082]
FIG. 6 is a block diagram showing a configuration of a wave height correction processor 30A according to the second embodiment of the present invention. In the second embodiment, in addition to correcting the calculation wave height Wh according to the change of the wave direction information Wd as in the first embodiment of FIG. 3, the means for correcting according to the wavelength Wl. Is added to further improve the accuracy of the correction wave height. This is because the wavelength Wl corresponds to the reference wave height based on actually measured data over a long period, the reference wave height is high when the wavelength Wl is large, the reference wave height is low when the wavelength Wl is small, and the wavelength Wl. Is also based on the fact that it has been confirmed to have a large correlation with the reference wave height.
[0083]
In FIG. 6, similarly to FIG. 3, the wave height correction processor 30A receives the wave direction information Wd, the calculated wave height Wh, the wavelength information Wl, and the wave velocity information Wvc from the wave calculation processor 20 every predetermined time (for example, 2 minutes). Interval).
[0084]
In the wave height correction processor 30A of FIG. 6, the division output from the division circuit 308 is supplied to the first regression correction circuit 309 after being multiplied by the multiplication circuit 315, and the multiplication circuit 315 is multiplied. Wavelength signal deriving means 34 for generating a wavelength correction coefficient Lc supplied as a coefficient. Since the other configuration is the same as that of the wave height correction processor 30 in FIG. 3, the corresponding components are denoted by the same reference numerals and the description thereof is omitted.
[0085]
In FIG. 6, the wavelength signal deriving means 34 receives the wavelength information W1 from the wave calculation processor 20, and limits the maximum and minimum values to a specified value by the wavelength limiter 318 to adjust the correction effect. A coefficient Lc is derived, and this wavelength correction coefficient Lc is supplied to the multiplier circuit 315.
[0086]
The wavelength limiter 318 may define only the maximum, and the maximum predetermined value is set to 120 m (coefficient 1.2) in order to avoid an error when the wave becomes a swell wave. The minimum predetermined value is not necessarily provided, but may be set for operational safety (for example, 1 m, coefficient 0.01).
[0087]
The wavelength correction coefficient Lc is actually obtained by multiplying the wavelength information Wl by a predetermined coefficient. However, since this coefficient can be absorbed by the regression coefficient in the first regression correction circuit 309, here, in order to avoid complexity. Omitted.
[0088]
The output of the multiplication circuit 315 corrected with the wavelength correction coefficient Lc is subjected to regression correction by the first regression correction circuit 309. The regression equation and its regression coefficient in the first regression correction circuit 309 are naturally adapted to the wavelength-corrected value. A linear regression equation (y = a + bx) can also be used as this regression equation. The output of the division circuit 308 is directly supplied to the second regression correction circuit 310.
[0089]
When the accuracy of the wavelength information Wl is good, the output of the first regression correction circuit 309 corrected by the wave direction correction coefficient Ac and the wavelength correction coefficient Lc is adopted, and when the accuracy of the wavelength information Wl cannot be obtained. The output of the second regression correction circuit 309 that has been corrected only by the wave direction correction coefficient Ac is employed.
[0090]
The selection is performed by switching the switching circuit 311 according to the output of the comparator 314. Accordingly, whether or not good sea surface reflection is obtained and the wavelength accuracy is good is determined according to the sea surface reflection detection signal Si and the average wave direction change signal Wdav from the sea surface reflection detection circuit 313 as in FIG. .
[0091]
As described above, in the wave height correction processor 30A, the calculation wave height information Wh sequentially output from the wave operation processor 20 in the correction calculation unit 32 is converted into the average wave direction change signal ΔWdav according to the average wave direction change signal ΔWdav. When the average wave direction change signal ΔWdav is large, the calculation is performed so as to decrease when the average wave direction change signal ΔWdav is large. Further, the calculated result is calculated and output according to the wavelength correction coefficient Lc so as to increase when the wavelength correction coefficient Lc is large and to decrease when the wavelength correction coefficient Lc is small.
[0092]
Therefore, since the correction is sequentially performed with the wave direction correction coefficient Ac and the wavelength correction coefficient Lc that are correlated with the calculated wave height information Wh, the accuracy of the correction wave height Whc output from the wave height correction processor 30A is further improved.
[0093]
FIG. 7 is a block diagram showing a configuration of a wave height correction processor 30B according to the third embodiment of the present invention. In the third embodiment, as in the second embodiment of FIG. 6, in addition to correcting the calculated wave height Wh according to the change in the wave direction information Wd, according to the wavelength information Wl. By adding a correcting means, the accuracy of the corrected wave height is further improved.
[0094]
In the third embodiment of FIG. 7, the information on the wavelength for obtaining the wavelength correction coefficient Lc is based on the period information Wt from another observation device or the like instead of the wavelength information Wl from the wave calculation processor 20. To get it.
[0095]
Since the period information Wt has a relationship according to a specific conversion formula between the wavelength and the wavelength, if the period information Wt is obtained continuously and accurately without being affected by the state of sea surface reflection, the wave direction correction coefficient Ac and Since sequential correction with the wavelength correction coefficient Lc can always be performed, the corrected wave height Whc with improved accuracy is continuously obtained from the wave height correction processor 30B.
[0096]
In FIG. 7, unlike in FIGS. 3 and 6, wave direction information Wd and calculated wave height information Wh are input to the wave height correction processor 30B every predetermined time (for example, every 2 minutes), unlike the wave operation processor 20. At the same time, as shown in FIG. 8, period information Wt is input from a separately provided wave period input device 50. In FIG. 8, the wavelength information Wl and the wave velocity information Wvc are also expressed so as to be input to the wave height correction processor 30B, but this is also used for the description of the next embodiment.
[0097]
In the wave height correction processor 30B shown in FIG. 7, the division output from the division circuit 308 is supplied to the first regression correction circuit 309 after being multiplied by the multiplication circuit 315, and the multiplication circuit 315 is multiplied. A wavelength signal deriving unit 34 for generating a wavelength correction coefficient Lc supplied as a coefficient is provided.
[0098]
In FIG. 7, the wavelength signal deriving unit 34 receives the period information Wt and converts the period information Wt input by the period / wavelength conversion circuit 316 into wavelength information Wl. The conversion from the period information Wt to the wavelength information Wl is performed by the conversion formula “Wl = 1.56 Wt ² To follow. This conversion formula is known as a conversion formula related to waves, and is described in Hidetaka Tsuji, Tsuguo Matsumoto, Kei Umi Saito, “Umi no Nami”, Jinshokan, P3. The converted wavelength information Wl is derived by the wavelength limiter 318 to limit the maximum and minimum values to a prescribed value and derive a wavelength correction coefficient Lc that adjusts the effect of correction, and supplies this wavelength correction coefficient Lc to the multiplier circuit 315.
[0099]
The wave cycle input device 50 for obtaining the cycle information Wt may be an observation device that can obtain the cycle information Wt with high accuracy. For example, considering a combination (set) with the radar 10, a radar that irradiates a pencil beam installed in the vicinity of the radar 10 and receives a reflected wave is used. Wave period information can be obtained by using the temporal change of the reflected wave by the pencil beam. In addition, a buoy is floated on the sea surface, and wave period information can be obtained by using data of a speedometer and an accelerometer mounted on the buoy.
[0100]
The wave cycle input device 50 may output cycle information Wt obtained by visual observation. Visual wave period observation is obtained by measuring the time it takes for the target to reach the next wave peak from the first wave peak. The period usually has almost no fixed value, so select and observe several clearly large waves (usually 10-20 waves) and take the average value.
[0101]
In the wave height correction processor 30B of FIG. 7, since the period information Wt is continuously obtained from the outside, the selection means 33 of FIG. 6 is unnecessary, and the second regression correction circuit 310 can also be deleted. Other configurations are the same as those of the wave height correction processors 30 and 30A of FIG. 3 and FIG. 6, so the corresponding components are denoted by the same reference numerals and the description thereof is omitted.
[0102]
Therefore, in the wave height correction processor 30B in FIG. 7, the multiplication circuit 315 divides the signal from the division circuit 308, that is, the signal whose wave direction is corrected by dividing the calculated wave height information Wh by the wave direction correction coefficient Ac, into the wavelength correction coefficient Lc. Further correct with. Therefore, since the wave direction correction coefficient Ac and the wavelength correction coefficient Lc respectively correlated with the calculated wave height information Wh are always sequentially corrected, the corrected wave height Whc with improved accuracy is always obtained from the wave height correction processor 30A. .
[0103]
FIG. 9 is a block diagram showing a configuration of a wave height correction processor 30C according to the fourth embodiment of the present invention. In the fourth embodiment, the wave height correction processor 30A in the second embodiment of FIG. 6 is configured so that it can cope with the case where the period information Wt is obtained from the outside. That is, the wavelength signal deriving means 34 in FIG. 6 is provided with the period / wavelength conversion circuit 316 and the switching circuit 317 in the third embodiment in FIG.
[0104]
The switching circuit 317 passes the wavelength information converted by the period / wavelength conversion circuit 316 when the period information Wt is obtained from the outside, and passes the wavelength information Wl when the period information Wt is not obtained. Switching which one is passed can be performed by a switching signal CS. When passing the converted wavelength information, the switching circuit 311 selects the output of the first regression correction circuit 309. In order to be selected in this way, the comparator 314 is controlled by the switching signal CS as shown in the figure, or the switching circuit 311 is directly switched.
[0105]
The configuration other than the switching of the switching circuit 317 and the switching circuit 311 is the same as the configuration in the wave height correction processors 30A and 30B in FIGS.
[0106]
Therefore, the wave height correction processor 30C of FIG. 9 further corrects the wave direction corrected signal divided by the wave direction correction coefficient Ac with the wavelength correction coefficient Lc based on the wavelength information W1 from the wave calculation processor 20, The accuracy of the correction wave height Whc is further improved. When the wavelength period information Wt is obtained from the outside, the correction is always performed using the wavelength correction coefficient Lc. Therefore, the corrected wave height Whc with improved accuracy is always obtained.
[0107]
Further, as the wave calculation processor 20, the wave calculation processor of FIG. 10 can be used. The wave arithmetic processor of FIG. 10 acquires a sea surface reflection signal by the radar 10 and records a radar signal of a large number of scans (for example, 32 scans) in the radar signal acquisition means 61. Next, the radar signal for 32 scans is converted from polar coordinates to rectangular coordinates by the three-dimensional FFT means 62, and three-dimensional FFT processing is performed to obtain a three-dimensional spectrum I (k, ω). Next, in the wave spectrum estimation means 63, the calculated three-dimensional spectrum I (k, ω) is converted into a dispersion relation equation ω which is a theoretical equation of the wave. ² Filter by applying to = gk, remove noise, and extract only the three-dimensional spectrum F (k, ω) for the original wave. Then, the sea state analysis means 64 calculates the wave information of the wave direction information Wd, the wave height information Wh, the wavelength information Wl, and the wave speed information Wvc using the extracted three-dimensional spectrum F (k, ω). A radar wave measuring device disclosed in Non-Patent Document 1 can be used as the wave calculation processor 20.
[0108]
【The invention's effect】
According to the radar wave observation apparatus of the present invention, the wave height obtained by wave calculation processing from the sea surface reflection signal of the radar is corrected using other wave calculation processing results (wave direction, wavelength, wave velocity), It is possible to accurately match the reference wave height measured with a sonic wave height meter or the like. This contributes to the design of structures such as breakwaters, revetments, coastal dikes, and safe and efficient operation of ships, and also enables effective operation such as maritime control.
[0109]
Further, based on the fact that the wave direction change value has a large correlation with the peak value, the calculated wave height becomes high when the average wave direction change signal is small and becomes low when the average wave direction change signal is large. Since the calculated result is subjected to regression correction by the regression correction means and output, a highly accurate observation peak value can be obtained.
[0110]
The correction calculation means has a plurality of regression correction means having different regression coefficients, and selects an appropriate regression correction means according to the magnitudes of the sea surface reflection detection signal and the wave direction change signal. The wave height can be corrected.
[0111]
The calculated wave height is calculated to be high when the wave direction change signal is small, and to be low when the wave direction change signal is large, and the calculated result is calculated according to the wavelength correction coefficient. It is calculated and output so that it increases when it is large and decreases when the wavelength correction coefficient is small. As a result, the correction is sequentially performed using the wave direction correction coefficient and the wavelength correction coefficient that have a correlation with the calculated wave height, so that the accuracy of the correction wave height output from the wave height correction processor is further improved.
[0112]
Further, the correction of the wave height does not require other peripheral devices, the radar wave observation device can be configured at low cost, and the installation thereof becomes easy. In addition, when the period information can be obtained by another device or visual observation, it is possible to continuously obtain the corrected wave height with improved accuracy according to the state of the sea surface.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a radar wave observation apparatus according to the present invention.
FIG. 2 is a block diagram of a wave arithmetic processor used in the present invention.
FIG. 3 is a block diagram of a wave height correction processor according to the first embodiment of the present invention.
FIG. 4 is a diagram for explaining a wave direction average processing method;
FIG. 5 is a diagram illustrating a wave direction 180 degree process.
FIG. 6 is a block diagram of a wave height correction processor according to a second embodiment of the present invention.
FIG. 7 is a block diagram of a wave height correction processor according to a third embodiment of the present invention.
FIG. 8 is a diagram showing another overall configuration of the radar wave observation apparatus of the present invention.
FIG. 9 is a block diagram of a wave height correction processor according to a fourth embodiment of the present invention.
FIG. 10 is a block diagram of another wave arithmetic processor used in the present invention.
[Explanation of symbols]
10 Radar
20 Wave arithmetic processor
21 Radar signal acquisition means
22 Radar interference detection means
23 Two-dimensional calculation means
24 Averaging means
25 Wave spectrum estimation means
26 Sea state analysis means
30 Wave height correction processor
31 Wave direction change signal deriving means
301 first average processing circuit
302 Subtraction circuit
303 Absolute value conversion circuit
304 Wave direction 180 degree processing circuit
305 Second average processing circuit
32 Correction calculation means
306 Angle limiter
307 power circuit
308 Division circuit
309 First regression correction circuit
310 Second regression correction circuit
315 Multiplier circuit
33 Selection means
311 switching circuit
312 Third average processing circuit
313 Sea surface reflection detection circuit
314 Comparator
34 Wavelength signal deriving means
316 period / wavelength conversion circuit
317 switching circuit
318 Wavelength limiter
40 Output device
50 Wave period input device
61 Radar signal acquisition means
62 3D FFT means
63 Wave spectrum estimation means
64 Sea state analysis means
Wd wave direction information
Wh wave height information
Wl wavelength information
Wvc wave speed information
Whc corrected wave height
Wt cycle information
ΔWdav averaged wave direction change signal
Ac wave direction correction coefficient
Si sea surface reflection detection signal
Ac wave direction correction coefficient
Lc Wavelength correction coefficient

Claims (17)

A radar image is obtained from a radar reflection signal from the sea surface, the radar image is Fourier transformed, and a theoretical wave equation is applied to the transformation result, thereby extracting a spectrum relating to the wave, and using the extracted spectrum, Wave calculation processor for calculating wave information including wave direction information and wave height information,
A wave direction change signal deriving means for obtaining a wave direction change signal representing a change amount of the wave direction information based on the wave direction information sequentially output from the wave operation processor based on a predetermined direction, from the wave operation processor The wave height signal corresponding to the wave height information that is sequentially output is calculated so as to increase when the wave direction change signal is small and to decrease when the wave direction change signal is large according to the wave direction change signal. And a wave height correction processor configured to include a correction calculation means for outputting the radar wave observation device. The wave height correction processor further includes correction wave height averaging means for obtaining a correction wave height by averaging the output from the correction calculation means for a predetermined period,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. 2. The radar wave observation apparatus according to claim 1, wherein the calculated result is subjected to regression correction by a regression correction means and output. The correction calculation means has a plurality of regression correction means each having a different regression coefficient as the regression correction means,
Further, the sea surface reflection detection means for receiving the wavelength information and the wave speed information sequentially output from the wave calculation processor and obtaining a sea surface reflection detection signal from the ratio of the theoretical wave speed and the wave speed information based on the wavelength information, the sea surface reflection detection Signal and the wave direction change signal are input, the sea surface reflection detection signal is compared with a threshold value defining a predetermined range, the wave direction change signal is compared with a predetermined threshold value, and a selection command signal corresponding to the comparison result is output. 2. A selection means comprising: a comparison means for performing selection; and a switching means for inputting the selection command signal and switching and outputting the outputs of the plurality of regression correction means according to the selection command signal. 2. A radar wave observation device according to 2. The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, 4. The method according to claim 1, further comprising power means, division means for dividing the wave height signal by the wave direction correction coefficient, and the regression correction means for performing regression correction on the division output of the division means and outputting the result. Radar wave observation device described in 1. A radar image is obtained from a radar reflection signal from the sea surface, the radar image is Fourier transformed, and a theoretical wave equation is applied to the transformation result, thereby extracting a spectrum relating to the wave, and using the extracted spectrum, Wave calculation processor for calculating wave information including wave direction information and wave height information,
A wave direction change signal deriving means for obtaining a wave direction change signal representing a change amount of the wave direction information based on the wave direction information sequentially output with reference to a predetermined direction from the wave arithmetic processor;
Wavelength signal deriving means for obtaining a wavelength correction coefficient representing the magnitude of the wavelength;
The wave height signal corresponding to the wave height information sequentially output from the wave arithmetic processor becomes high when the wave direction change signal is small and low when the wave direction change signal is large according to the wave direction change signal. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. A radar wave observation apparatus comprising: a wave height correction processor configured to include a calculation means. 6. The radar wave observation apparatus according to claim 5, wherein the wavelength signal deriving unit obtains the wavelength correction coefficient based on wavelength information sequentially output from the wave calculation processor. The wave height correction processor further includes correction wave height averaging means for obtaining a correction wave height by averaging the output from the correction calculation means for a predetermined period,
The wavelength signal deriving means obtains the wavelength correction coefficient based on the wavelength information sequentially output from the wave arithmetic processor,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. The radar wave observation apparatus according to claim 6, wherein the wave is output after being subjected to regression correction by a regression correction means. The correction calculation means has a first regression correction means as the regression correction means and a regression coefficient different from the regression coefficient of the first regression correction means, and the wave height signal is changed according to the averaged wave direction change signal. Having a second regression correction means for regression correction of the calculated calculation result;
Further, the sea surface reflection detection means for receiving the wavelength information and the wave speed information sequentially output from the wave calculation processor and obtaining a sea surface reflection detection signal from the ratio of the theoretical wave speed and the wave speed information based on the wavelength information, the sea surface reflection detection The signal and the wave direction change signal are input, the sea surface reflection detection signal is compared with a threshold value that defines a predetermined range, the wave direction change signal is compared with a predetermined threshold value, and the comparison result is within the predetermined range and the predetermined threshold value. Comparison means for selecting the first regression correction means when it is below, and outputting a selection command signal for selecting the second regression correction means otherwise, the selection command signal is inputted, 8. The radar wave observation apparatus according to claim 7, further comprising selection means having switching means for switching and outputting the outputs of the first and second regression correction means according to the selection command signal. The wavelength signal deriving means includes a wavelength limiter that limits at least an upper limit value of a wavelength correction coefficient obtained from wavelength information sequentially output from the wave calculation processor,
The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, Power means, division means for dividing the wave height signal by the wave direction correction coefficient, multiplication means for multiplying the division output of the division means by the limited wavelength correction coefficient from the wavelength signal deriving means, and multiplication 8. The method according to claim 7, further comprising: a first regression correction unit that performs regression correction to output a multiplication output of the unit, and a second regression correction unit that performs regression correction to output the division output of the division unit. , 8 Radar wave observation device. 6. The radar wave observation apparatus according to claim 5, wherein the wavelength signal deriving unit obtains the wavelength correction coefficient based on period information inputted from outside. The wave height correction processor further includes correction wave height averaging means for obtaining a correction wave height by averaging the output from the correction calculation means for a predetermined period,
The wavelength signal deriving means converts the period information according to a predetermined conversion formula to obtain the wavelength correction coefficient,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. The radar wave observation apparatus according to claim 10, wherein regression correction is performed by regression correction means and output. The wavelength signal deriving means restricts at least an upper limit value of the wavelength correction coefficient from the period / wavelength conversion means, and a period / wavelength conversion means for converting the period information into the wavelength correction coefficient according to a predetermined conversion formula. Output wavelength limiter,
The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, Power means, division means for dividing the wave height signal by the wave direction correction coefficient, multiplication means for multiplying the division output of the division means by the limited wavelength correction coefficient from the wavelength signal deriving means, and multiplication The radar wave observation apparatus according to claim 11, further comprising: a regression correction unit that performs regression correction to output the product output of the unit. The wavelength signal deriving means selects either a wavelength correction coefficient obtained based on wavelength information sequentially output from the wave calculation processor or a wavelength correction coefficient obtained based on periodic information input from the outside. The radar wave observation device according to claim 5, wherein the radar wave observation device is a device for outputting a radar wave. The wave height correction processor further includes correction wave height averaging means for obtaining a correction wave height by averaging the output from the correction calculation means for a predetermined period,
The wavelength signal deriving means is either a wavelength correction coefficient obtained from wavelength information sequentially output from the wave calculation processor, or a wavelength correction coefficient obtained by converting the period information according to a predetermined conversion formula. To select and output,
The wave direction change signal deriving means takes the difference between the average value of the wave direction information for a predetermined period and the latest wave direction information as the wave direction change signal, and averages the absolute value of the difference To obtain a wave direction change signal,
The correction calculating means increases the wave height signal according to the average wave direction change signal when the average wave direction change signal is small and decreases when the average wave direction change signal is large. Further, according to the wavelength correction coefficient, the calculation result is calculated so as to increase when the wavelength correction coefficient is large and to decrease when the wavelength correction coefficient is small. The radar wave observation apparatus according to claim 13, wherein the wave is output after being subjected to regression correction by a regression correction means. The correction calculation means has a first regression correction means as the regression correction means and a regression coefficient different from the regression coefficient of the first regression correction means, and the wave height signal is changed according to the averaged wave direction change signal. Having a second regression correction means for regression correction of the calculated calculation result;
Further, the sea surface reflection detection means for receiving the wavelength information and the wave speed information sequentially output from the wave calculation processor and obtaining a sea surface reflection detection signal from the ratio of the theoretical wave speed and the wave speed information based on the wavelength information, the sea surface reflection detection The signal and the wave direction change signal are input, the sea surface reflection detection signal is compared with a threshold value that defines a predetermined range, the wave direction change signal is compared with a predetermined threshold value, and the comparison result is within the predetermined range and the predetermined threshold value. Comparison means for selecting the first regression correction means when it is below, and outputting a selection command signal for selecting the second regression correction means otherwise, the selection command signal is inputted, And switching means for switching and outputting the outputs of the first and second regression correction means according to the selection command signal, and the wavelength signal deriving means converts the period information according to a predetermined conversion formula. And if you have selected a wavelength correction coefficient characterized by having a selection means adapted to select the first corrected return means, radar wave observing apparatus according to claim 14. The wavelength signal derivation means includes a period / wavelength conversion means for converting the period information into a wavelength correction coefficient according to a predetermined conversion formula, a wavelength correction coefficient obtained from the wavelength information, and a wavelength correction from the period / wavelength conversion means. A switching unit that receives a coefficient and selects and outputs one of the wavelength correction coefficients according to the switching signal; and a wavelength limiter that outputs at least an upper limit value of the wavelength correction coefficient from the switching unit. Have
The correction calculation means derives a wave direction correction coefficient by giving a predetermined exponent to the wave direction change signal limited by the angle limiter and the angle limiter for limiting the maximum and minimum of the wave direction change signal, Power means, division means for dividing the wave height signal by the wave direction correction coefficient, multiplication means for multiplying the division output of the division means by the limited wavelength correction coefficient from the wavelength signal deriving means, and multiplication 15. The apparatus according to claim 14, further comprising: a first regression correction unit that performs regression correction to output the multiplication output of the unit, and a second regression correction unit that performs regression correction to output the division output of the division unit. , 15 Radar wave observation device. The wave direction change signal deriving unit sequentially receives the wave direction information and outputs an average value of the wave direction information for a predetermined period, and an average of the first wave direction average processing unit Subtracting means for taking a difference between the value output and the latest wave direction information, an absolute value converting means for converting the output of the subtracting means into an absolute value, and an output of the absolute value converting means, and receiving 0 to 180 degrees Less than 360 degrees and less than 360 degrees are output by subtracting from 360 degrees, and the output of the wave direction 180 degree processing means is averaged for a predetermined period, 17. The radar wave observation device according to claim 1, further comprising wave direction averaging processing means for outputting the averaged wave direction change signal.

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